为什么我的自定义异常没有被重新抛出/捕获？

Question

所以我有一个名为 Digicel 的类和另一个名为 AdminGui 的类。 我已将 Digicel 类导入到 AdminGui 类中，因为它们位于不同的包中。 我的项目中还有其他类，但我认为不需要针对此问题提及它们。

我在 Digicel 类中有一个名为 addCustomer 的函数，该函数将客户的信息写入文本文件。 但是我想检查文件中的记录，以确保客户的 ID 号是唯一的，并且文件中不存在。 为此，我创建了一个名为 UniqueValueException 的自定义异常，它扩展了 Exception 类。

唯一值异常类

public class UniqueValueException extends Exception {
    public UniqueValueException(String message) {
        super(message);
    }
}

在 Digicel 类中，我有 addCustomer 函数，用于写入文件，以及 checkCustomerUniqueValues，用于在文件中搜索相同的客户 ID。

检查客户唯一值函数

    public static void checkCustomerUniqueValues(Customer c) throws UniqueValueException{
        Scanner inFileStream = null;
        String custID = "";
        String name = "";
        float creditBalance = 0;
        String telephone = "";
        String address = "";
        try {
            inFileStream = new Scanner(new File("Digicel_Customers.txt"));
            while (inFileStream.hasNext()) {
                custID = inFileStream.next();
                name = inFileStream.next();
                creditBalance = inFileStream.nextFloat();
                telephone = inFileStream.next();
                address = inFileStream.nextLine();
                if (custID.equals(c.getCustID())) {
                    //inFileStream is closed in finally block
                    throw new UniqueValueException("Customer ID already exists.");
                }
                else if(telephone.equals(c.getTelephone().toString())){
                    throw new UniqueValueException("Telephone number already in use.");
                }
            }   
        } 
        catch (UniqueValueException e) {
            e.printStackTrace();
        }
        catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        }
        finally{
            if(inFileStream != null) {
                try {
                    inFileStream.close();
                }catch(Exception e) {
                    System.err.println("\nAn unexpected error occured.");
                }   
            }
        }
    }

添加客户功能

public String addCustomer(Customer c) throws UniqueValueException { 
        FileWriter outFileStream = null;
        Scanner input = null;
        input = new Scanner(System.in);
        try {
            outFileStream = new FileWriter(new File("Digicel_Customers.txt"), true);
            try {
                checkCustomerUniqueValues(c);
            } 
            catch(UniqueValueException e){
                System.out.println("Inside addCustomer() method");
                throw e;
            }
            catch(Exception e) {
                throw e;
            }


            if(c.getCustID().length() != 11){
                return "TRN is invalid - Length: " + c.getCustID().length();
            }
            
            String newCustomer = c.getCustID() + "\t" + c.getName() + "\t" + c.getCreditBalance() + "\t" + c.getTelephone().toString() + "\t" +  c.getAddress() +  "\n";    
            outFileStream.write(newCustomer);
            System.out.println("Information saved successfully!");
            super.addCustomer(c);
            digicelCustomerCount++;
            return("");
            
        }
        catch(Exception e) {
            return("\nAn unexpected error occured.");
        }
        finally {
            if(outFileStream != null) {
                try {
                    outFileStream.close();
                }catch(Exception e) {
                    System.err.println("\nAn unexpected error occured.");
                }       
            }
            if(input != null) {
                input.close();
            }
        }
        
    }

在 AdminGui 类中，我在按钮上有一个动作侦听器，用于传递文本字段的信息以在 Digicel 中添加客户功能。

        addUserButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                Customer c;
                String returnString = "";
                if(!customerIdText.getText().equals("   -   -   ") && !lastNameText.getText().equals("User Last Name") && !addressText.getText().equals("Address") && !phoneText.getText().equals("876-000-0000")){
                    c = new Customer(customerIdText.getText(), lastNameText.getText(), addressText.getText(), new Telephone(Integer.parseInt(phoneText.getText().substring(0,3)), Integer.parseInt(phoneText.getText().substring(4,7)), Integer.parseInt(phoneText.getText().substring(8,12))));
                    try{
                        returnString = adminUser.addCustomer(c);
                        if(returnString != ""){
                            JOptionPane.showMessageDialog(parentFrame,returnString + " "+ phoneText.getText() + "\nPrefix - " + phoneText.getText().substring(0,3),"Form Error",JOptionPane.ERROR_MESSAGE);
                        }
                        else{
                        JOptionPane.showMessageDialog(parentFrame,"Information Saved!","Form Submitted",JOptionPane.INFORMATION_MESSAGE);
                        }
                    }
                    catch(UniqueValueException e1){
                        JOptionPane.showMessageDialog(parentFrame,returnString,"Form Error",JOptionPane.ERROR_MESSAGE);
                    }
                }
                else{
                    JOptionPane.showMessageDialog(parentFrame,"All fields must be filled","Form Error",JOptionPane.ERROR_MESSAGE);
                }
            }
        });

我的问题是，在 checkCustomerUniqueValues 方法中，抛出异常但它没有在 addCustomer 方法中捕获，即使它在 try 块中调用。 checkCustomerUniqueValues 中抛出的异常的错误消息显示在终端中，但堆栈中的其余代码仍在运行。 “信息保存成功！” 消息显示在底部。

OOPproject.teleCompanyPKG.UniqueValueException: Customer ID already exists.
        at OOPproject.teleCompanyPKG.Digicel.checkCustomerUniqueValues(Digicel.java:182)
        at OOPproject.teleCompanyPKG.Digicel.addCustomer(Digicel.java:121)
        at OOPproject.guiPKG.AdminGui$6.actionPerformed(AdminGui.java:444)
        at java.desktop/javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1972)
        at java.desktop/javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2313)
        at java.desktop/javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:405)
        at java.desktop/javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:262)
        at java.desktop/javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:279)
        at java.desktop/java.awt.Component.processMouseEvent(Component.java:6617)
        at java.desktop/javax.swing.JComponent.processMouseEvent(JComponent.java:3342)
        at java.desktop/java.awt.Component.processEvent(Component.java:6382)
        at java.desktop/java.awt.Container.processEvent(Container.java:2264)
        at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:4993)
        at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2322)
        at java.desktop/java.awt.Component.dispatchEvent(Component.java:4825)
        at java.desktop/java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4934)
        at java.desktop/java.awt.LightweightDispatcher.processMouseEvent(Container.java:4563)
        at java.desktop/java.awt.LightweightDispatcher.dispatchEvent(Container.java:4504)
        at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2308)
        at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2773)
        at java.desktop/java.awt.Component.dispatchEvent(Component.java:4825)
        at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:772)
        at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
        at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)
        at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
        at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
        at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:95)
        at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:745)
        at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:743)
        at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
        at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
        at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:742)
        at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
        at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
        at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
        at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
        at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
        at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)
Information saved successfully!

我真的很难解决它，因为我不知道为什么它没有被重新抛出。 请发送帮助。

Answer 1

您的checkCustomerUniqueValues方法捕获Exception类型的所有Exception ，并吞下它们：

        } catch (Exception e) {
            e.printStackTrace();
        }

由于UniqueValueException是Exception的子类型，因此 catch-block 会捕获它，并防止它传播到调用者。

Answer 2

在函数 checkCustomerUniqueValues 中，您在 try/catch 中抛出异常，以便在那里捕获（打印堆栈跟踪的位置），因此调用函数将继续，因为什么也没发生